Chair control



April 29, 19.6.9 'F. DOERN-ER CHAIR CONTROL;

' Sheet Filed 1 July 24, 196' INVE-NTOK FRANK DOEIQIEK ATTORNEY A ril29,'19e9- 1.00am, 3,441,311

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ua A 27 INVENTOK FRANK 'DOERNER ATTORNEY April 29,1969 F. DOERNER v CHAIR CONTROL OfS Sheet Filed Jul 24, 1967 mvzwrom FRANK IDOEKNER ATTOKNE Y United States Patent U.S. Cl. 297305 4 Claims ABSTRACT OF THE DISCLOSURE A chair control in which the spring mechanismthat resists the tilting action of the chair seat or back is mounted perpendicular to the pivotally connected frame members, the mounting for the spring of the mechanism being arranged and constructed so that the spring has axial deflection without lateral distortion when the spring deflects in response to the tilting of the seat or chair back.

Specification The chair control of the present invention comprises in general, the combination of a pair of main frame members pivotally connected together for limited movement about a primary axis between a first relative position and a second relative position; biasing means urging the said pair of frame members into said first relative position and yieldably resisting movement of the frame members towards said second relative position; said biasing means comprising a U-shaped mounting bracket having a bight portion, said bracket being connected to one of said pair of frame members for pivotal motion relative thereto during relative motion between the said pair of frame members; resilient means having one end seated on said bight portion; and compressing means reactivelyconnected to said pair of frame members and retaining said resilient means on said bight portion, said compressing means being mounted in floating relationship relative to said mounting bracket and in contact with the other end of said resilient means, said biasing means remaining in substantially constant alignment relative to the other of said pair of members.

In general, tilting movement in conventional controls employing tilter compression springs causes such springs to deform laterally. Such improper and inefiicient usage necessitates overdesigned and generally bulkier springs than those required for purely axial loading. Lateral deformation further precludes the substitution of other resilient means (e.g. shock absorbers). In order to conform to the present design criteria of trim chair profile, it is the present practice to locate the axes of these bulky springs very close to the primary axis of the controls main frame members. This crowding in turn limits the effective range of pivotal tilting movement of the movable members.

One object of the present invention is to overcome the above-outlined disadvantages by providing novel mounting means for permitting only axial deflection of the resilient means while permitting a larger degree of chair tilting movement.

Patented Apr. 29, 1969 For a thorough understanding of the present invention and its many advantages, reference is made to the following detailed description of one illustrative embodiment taken in conjunction with the accompanying drawings in which:

FIG. 1 is a side elevation view of a posture chair employing the chair control of the present invention;

FIG. 2 is a perspective view looking at the underside of a posture chair to show the chair control of FIG. 1;

FIG. 3 is a side elevation in cross-section through a line running front-to-back and centrally of the chair seat while the chair back is in its normal position;

FIG. 4 is a side elevation as in FIG. 3 with the chair back shown in its fully tilted osition;

FIG. 5 is an exploded perspective view of the elements of the chair control of FIG. 1.

As already stated, FIGS. 1 to 5 show the present invention as applied to a posture or secretarial chair. It will be readily apparent to persons skilled in the art from the following description that while the same is described in conjunction with this type of chair, the invention can be readily adapted to tilter chairs or to any other structure in which it is desirable to have one part tiltable relative to another part which may or may not be stationary itself. Consequently, the following detailed description is for the purpose of exemplifying the invention and not for the purpose of restricting same to the particular type of structure herein described.

FIG. 1 illustrates a posture or secretarial chair comprising a base 10 which is mounted on castors 11, and carries a threaded spindle 12 which has mounted on the top thereof a chair control according to the present invention, which chair control is generally indicated by the letter A and which will hereafter be more particularly described. A chair seat 13 is mounted on the chair control as hereinafter described, and a chair back 14 is supported by the chair control for rearward tilting movement from a substantial upright position.

The chair control A comprises a pair of main frame members 15, 16, member 15 being mountable in a fixed position on the chair spindle 12 with the other frame member 16 pivotally mounted on and movable relative to member 15. The chair control A further includes a tilt-resisting, spring-biasing means comprising; bracket 32; a resilient means consisitng of compression spring 40, and a compressing means comprising connecting rod 39, each of which means will hereafter be more particularly described.

The fixed frame member 15 serves as a chair seat support member for the chair control A and is attachable to the underside of the seat 13 in any known manner. The fixed frame member 15 includes a U-shaped plate 19 having spindle mount 20 attached thereto for mounting the fixed frame member 15 on the spindle 12 as described in a copending U.S. application. Spaced-apart flanged spiders 21, 22, one on each side of the control are attachable to the underside of the seat 13 and optionally attachable to the plate 19. A U-shaped pivot-bracket 23 having downwardly extending arms 23a, 23b is connected to the underside of plate 19. The downwardly extending arms 23a, 23b are bored as at 25, 26 to provide bearings for a pivot pin 24 which serves to pivotal- 3 1y connect the movable frame member 16 to the fixed frame member 15.

The movable frame member 16 is a U-shaped member with forwardly extending arms 17, 18 having apertures 28, 29, which receive the aforementioned pivot pin 24 for rearward tilting of the U-shaped member 16. The arms 17, 18 also have bushing 30, 31 by means of which a U-shaped mounting bracket 32 having a bight portion 38 is pivotally mounted to the arms 17, 18. A spacer bar 33, fitting into slots in said arms, serves to maintain the arms in constant relative alignment.

The pivotal mounting of the U-shaped mounting bracket 32 is effected by flanged bores 34, 35 formed in downwardly extending arms 41, 42 which receive bushings 30, 31. The bight portion 38 has a centrally located bore 36 of a diameter which is larger than the diameter of a connecting rod 33, to be hereinafter described, thus permitting free movement of the rod 39 through the bore 36. The spring biasing means comprises a spring 40, one end of which is flat-ground and seated on said bight portion 38, thus, in effect, recessing the spring into the space between the arms of the U-shaped member 1 6 and consequently reducing the profile of the chair control.

The tilt resisting, spring-biasing means, which includes the U-shaped mounting bracket 32, urges the chair back 14 to a normal or first position as illustrated in FIG. 3 in which the rear edge of the bight portion 38 is shown in abutment with a stop 37 on the fixed frame member 15.

The biasing means also includes the connecting rod 39, said rod having one end retained by the plate 19 adjacent stop 37, the shank of the bolt 39 passing through the bore 36 and through the axial cavity of the spring 40; the other end of the bolt being threaded and passing through a contoured washer 43 to threadably engage with a tension adjustment handwheel 27. By this construction, the spring 40 is captured between the bight 38 and the adjustable handwheel 27.

The operation of the invention is illustrated best by reference to FIGS. 3 and 4. FIG. 4 shows the U-shaped member 16 and chair back 14 in the position of maximum tilt. Stops 45 and 46 on the arms of U-shaped member 16 engage against the plate portion 19 of the fixed frame member 15 to limit the tilting movement of the chair back to this second position of maximum tilt. The maximum degree of deflection of the movable frame 1 6 may be further enhanced by shortening the arms -17, 18 or by lengthening the arms of the pivot bracket 23.

A comparison of FIGS. 3 and 4 shows that deflection of the U-shaped member 16 causes the bight portion 38- of the mounting bracket 32 to float or slide down the body of the connecting bolt 39, thus capturing and axially compressing the spring 40 between said bight portion, the washer and the adjustable handwheel 27. The flattened end of the compressed spring then reacts against said bight portion 38, urging the mounting bracket 32 (and the U-shaped member 16 connected pivotally thereto), upwards and towards the stop 37 located on the plate 19 of the fixed frame member 15. Under the urging of the axially compressed spring 40, the mounting bracket 32 moves pivotally to realign its bight portion 38 perpendicular to the reactive spring force.

The aforementioned pivotal motion of the bracket 32 relative to the U-shaped member 16, together with the freely floating motion of said bracket along the body of the connecting bolt 39, co-operate to restrict the compression of spring 40 to axial deflections and prevent the occurrence of substantial bending moments in the connecting bolt 39.

What I claim as new and desire to protect by Letters Patent of the United States is:

1. In a posture chair having a chair base, a spindle mounted in said chair base, a chair seat mountable on said spindle, and a chair back pivotally movable relative to said chair seat; a chair control comprising:

(a) a pair of main frame members pivotally interconnected for limited movement about a primary axis between a first relative position and a second relative position;

(b) biasing means located in spaced relation to said primary axis and urging the main frame members to one of said relative positions; said biasing means comprising:

(i) a U-shaped bracket having a pair of arms interconnected by a bight portion and pivotally connected at said arms to one of said main frame members;

(ii) resilient means having one end thereof seated on said bight portion;

(iii) compressing means having one end thereof in substantially fixed abutment with the other of said main frame members and adapted to retain the resilient means in seated position on said bight portion; said compressing means being mounted for floating relationship relative to said U-shaped bracket;

(0) one of said main frame members being mountable in a fixed position on said spindle and attachable to the underside of said chair seat; and wherein (d) the other main frame member is attachable to said chair back, whereby, upon the application of a rearward force on said chair back, said chair back moves causing pivotal movement between said main frame members towards said second relative position the resilient means is substantially axially deflected and said U-shaped bracket pivots relative to the said one main frame member maintaining the biasing means in substantially constant alignment with said other main frame member.

2. A chair control as defined in claim 1 wherein said compressing means comprises a headed bolt, passing through said U-shaped bracket and said resilient means, and an adjusting handwheel threadably engaged on said bolt; the head of the bolt being in substantially fixed abutment with said other main frame member and the handwheel adjustably retaining the resilient means on said bight portion.

3. In a posture chair having a chair base, a spindle mounted in said chair base, a chair seat mountable on said spindle, and a chair back pivotally movable relative to said chair seat; a chair control comprising:

(a) a pair of main frame members pivotally interconnected for limited movement about a primary axis between a first relative position and a second relative position;

(b) biasing means located in spaced relation to said primary axis and urging the main frame members to one of said relative positions; said biasing means comprising;

(i) a U-shaped bracket having a pair of arms interconnected by a bight portion and pivotally connected at said arms to one of said main frame members;

(ii) a helical compression spring having one end thereof seated on said bight portion;

(iii) compressing means having one end thereof in substantially fixed abutment with the other of said main frame members and adapted to retain the helical spring in seated position on said bight portion; said compressing means being mounted for floating relationship relative to said U-shaped bracket;

(c) one of said main frame members being mountable in a fixed position on said spindle and attachable to the underside of said chair seat; and wherein (d) the other main frame member is attachable to said chair back, whereby, upon the application of a rearward force on said chair back, said chair back moves causing pivotal movement between said main frame members towards said second relative position against the retentive urging of the helical compression spring, the said spring being substantially axially deflected and said U-shaped bracket pivoting relative to the said one main frame member thereby maintaining the biasing means in substantially constant alignment with said other main frame member. 4. A chair control as defined in claim 3 in which the compressing means comprises a headed bolt passing through said U-shaped bracket and said spring and an adjusting handwheel threadably engaging said bolt, the head of the bolt being in substantially fixed abutment with said other main frame member and the handwheel adjustably retaining the spring on said bight portion.

6 References Cited UNITED STATES PATENTS 2,140,058 12/ 1938 Sheldriek 297-305 2,563,951 8/1951 Mondy 297-306 2,662,586 12/ 1953 Cramer 297304 X 2,770,292 11/ 1956 Hamilton 297305 2,988,398 6/1961 Hamilton 297305 X 3,042,448 7/ 1962 Hamilton 297-301 3,356,414 12/1967 Doerner 297-301 BOBBY R. GAY, Primary Examiner. GLENN O. F-INCH, Assistant Examiner.

US. Cl. X.R. 297-349 

